ORIGIN OF BIASED GAP FLOW BEHIND MULTIPLE BLUFF BODIES IN A SIDE-BY-SIDE ARRANGEMENT.

The most striking feature in the wake interference of a row of normal flat plates arranged side by side is that the gap flow passing through the slit is biased either upward or downward in a stable way when the slit width is narrow. The origin of the biased flow and the mechanism of its stable biasing in one direction are investigated with water-tank experiments, numerical calculations and wind-tunnel experiments. The results show that the origin of biasing is strongly related to vortex shedding of each plate of a row, except for the case of very narrow slit width. Furthermore, it is suggested that the stability of a biased flow is particularly dependent on the behavior of the shear layer separated from the slit side of the plate on the unbiased side.